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A. Suárez (Barcelona, Spain) suggested that the measurement of hormonal values in CFS patients could help with diagnosis. There were no significant differences in ACTH parameters, but those with CFS had significant lowering of cortisol levels on the 3 days of exercise challenge testing. The differences in prolactin and growth hormone were not significantly different to controls.
Patients with fibromyalgia and/or CFS demonstrate sustained increases in gene expression for metabolite sensing receptors and βadrenergic receptors on leucocytes from 0.5 to 48 hours after exercise. This is the time when pain and fatigue worsen, even when muscles are inactive. This study by Alan Light (Utah, USA) suggests a predisposition for these receptors to increase dramatically after exercise, stress and infection. There is potential for the increases in gene expression to provide biomarkers.
Mary Ann Fletcher (Miami, USA) found that Neuropeptide Y (NPY) correlates with symptom severity in CFS. NPY was elevated in CFS compared to controls (p=.001) though there was some overlap between controls and CFS. This could be used as an assay to correlate with severity of illness, particularly in relation to psychological symptoms. NPY may be a potential biomarker for CFS and may be an important mediator of the illness itself, thus it is a target for therapeutic strategies. But for now it needs to be combined with other potential biomarkers such as gene expression. NPY needs radio-active assay and cheaper methods need to be developed.
Jonathon Kerr (London, UK) discussed the impact of stress on the outcome of viral infections. The context of stress was examined in relation to parvovirus B19 infection. 5 of 39 cases developed CFS and 4 of the 5 were viraemic at follow up. Stress index was significantly associated with the development of fatigue during the acute phase of illness, and also with chronic fatigue and arthritis in the 3 years following the acute B19 infection. Statistically it was found that a high stress index was the primary predictor of CFS/ME 1-3 years following the initial infection. Of the 5 cases followed, IV immunoglobulin therapy for B19 gave benefit, with 3 patients recovering completely. 2 withdrew because of headaches. 400mg.kg/day was given IV for 5 days.
The immunomodulatory effects of sodium oxybate in patients with α-wave intrusion during deep sleep was studied by Natalie Hone (Miami, USA). The average dose was 6.1gm daily. The study revealed a high rate of sleep disorders in CFS patients. α intrusion was the most common disorder, more so in women than men. 45.9% of patients had sleep apnoea (males more than females). Sodium oxybate had no significant immunomodulatory effects in patients with α intrusion, but sleep improved markedly clinically.